The weighted external path length of the binary tree in figure is ___________.

The following sequence of operations is performed on stack: PUSH (10),PUSH (20),POP,PUSH (10),PUSH (20),POP,POP,POP,PUSH (20),POP The sequence of the value popped out is:

If the binary tree in figure is traversed in inorder, then the order in which the nodes will be visited is ______

Find the minimum sum of products form of the logic function
$$f\left( {A,B,C,D} \right) = \sum d \left( {3,11,12,14} \right)$$
Where $$m$$ and $$d$$ denote the minterms and don't cares respectively.